1. Field of the Invention
This invention relates to cluster bombs, and more particularly to cluster bombs having facilities for communicating with each of the individual bomblets which are released when the bomb is dropped.
2. Description of the Prior Art
Cluster bombs have been used for some time to provide area coverage from a single bomb drop. Up to several hundred bomblets are carried within a single outer housing or canister, which separates into two parts when dropped from an aircraft and releases the bomblets. The individual bomblets ideally fall in a predetermined dispersion pattern to cover a large area. Some cluster bombs have no facilities for communicating with individual bomblets, and the bomblets explode upon impact or after a built-in delay period. In a more sophisticated type of cluster bomb, each of the individual bomblets is connected to a central controller by means of a wire harness, with separate cables running from the harness to each individual bomblet. The use of such cables makes it possible to communicate with the bomblets after they have been positioned in the bomb canister, for purposes such as arming the bomblets or providing a common detonation delay time to each of the bomblets.
While the use of such wire harness connections provides greater versatility in the applications for which the cluster bomb may be used, it also limits the performance of the bomb. It is generally desirable that the bomblet dispersion pattern be homogeneous over a large area. The forces acting on the bomblets as they are released from the cluster bomb are critical in determining the dispersion pattern, with only a few ounces of force on each bomblet being sufficient to greatly distort the pattern. One problem with the prior art wire harness approach has been that, in order to provide communication with the bomblets, the wire harnesses have had their cables mechanically connected directly to each bomblet. When the bomblets are released, they must then be disconnected from their respective cables in order to fall freely. Various attempts have been made to disconnect the bomblets without adversely effecting their dispersion pattern, but none have been entirely successful.
In one prior art arrangement, an explosive device is provided on each bomblet to separate the bomblet from its electrical cable upon bomb release. While this approach effectively disconnects the cable, the explosive devices impose relatively large forces upon their respective bomblets which tend to spoil the dispersion pattern. Low force mechanical separation devices have also been proposed, but connectors with such devices tend to be quite unreliable, and can still significantly disrupt the dispersion pattern. Another problem is that, if too much force is imparted to the bomblets when they are released, the bomblets can tumble as they drop. Since the bomblets are generally armed by a rotating fin arrangement that is turned by air pressure as the bomblets rapidly fall and causes an arming mechanism to activate, a tumbling motion can keep the fins from rotating and thereby prevent the bomblet from arming.
In addition to the separation problems mentioned above, the wire harness approach is quite expensive, in large part because it requires a separate cable for each of typically several hundred bomblets.
In a companion U.S. patent application by Edward V. LaBudde, Ser. No. 590,215, filed Mar. 16, 1984, and entitled "Cluster Bomb System and Method", a new type of cluster bomb is described in which each of the bomblets is provided with an individual programmable detonator control. A signal transmission means electromagnetically transmits program information signals to the vicinity of each bomblet, while an electromagnetic signal coupler within each bomblet provides an interface between the transmission means and the detonator control to program the detonator control in response to program information signals delivered by the transmission means. In the preferred embodiment the signal transmission means is an electrically conductive wire positioned adjacent to, but mechanically detached from, each of the bomblets. The wire serves as a primary transformer winding, each bomblet being provided with a multi-turn secondary winding to receive signals from the wire. The wire preferably extends through an opening in each bomblet, with the secondary windings disposed around the periphery of the openings. In order to rapidly pull the wire away when the bomb canister opens without imparting any significant force to the bomblets, the wire is mechanically attached to the canister at selected locations, and the canister is adapted upon opening to sever the wire and pull it away from the bomblets.